IELTS Academic Reading Test 42

allergy testing

Allergic reactions are triggered by the contact, inhalation, or ingestion of a number of different allergens. Some of the most common allergens are made up of proteins found in plants, mold, food, venom, animal skin, and medication. Symptoms of allergic reactions range from mild irritation such as itching, wheezing, and coughing to life-threatening conditions related to the respiratory and gastrointestinal organs. Serious allergic reactions are more likely to result from food, drugs, and stinging insects. A person does not become allergic to a particular substance until after the first exposure. However, in some cases, even trace amounts of a substance, such as peanuts or seafood in a mother’s breast milk, can cause an allergic reaction in a subsequent exposure.

A variety of allergy tests are available for determining specific substances that trigger allergic reactions in individuals. Allergists, also known as immunologists, are trained in selecting the types of tests that are both safe and appropriate, depending on the suspected allergies. By using allergen extracts, tiny amounts of commonly bothersome allergens (usually in the form of purified liquid drops), immunologists are often able to isolate which substances cause reactions in allergy sufferers.

One of the most common types of environmental allergy tests is the skin- prick test. This technique involves placing small drops of potential allergen onto the skin of the forearm about one to two inches apart. After the drops are placed on the arm, a needle is used to puncture the skin at the site of each drop. (Though the procedure is virtually painless, this test is often done on the upper back of children to prevent them from seeing the needle.) If an allergy is present, an allergic antibody called immunoglobulin E (IgE) will activate a special cell called a mast cell. Mast cells release chemicals (also known as mediators) that cause itching and swelling. The most common mediator is histamine. Histamine is what causes the controlled hive known as a wheal and flare. The white wheal is the small raised surface, while the flare is the redness that spreads out from it. In an uncontrolled allergic reaction, wheals and flares can get much bigger and spread all over a person’s body. Results from a skin test can usually be obtained within 20 to 30 minutes, while the reaction usually fades within a few hours.

Another test that is very similar to the skin-prick test is the intradermal allergy test. This involves placing the allergen sample under the skin with a syringe. The intradermal test involves more risk and is usually saved for use if the allergy persists even after a skin-prick test comes back negative. People who have experienced serious allergic reactions called anaphylactic reactions are not advised to have these types of tests. These allergy sufferers may be hypersensitive to even trace amounts of the allergens when they are introduced into the blood. Anaphylaxis is an allergic reaction that affects the whole body and is potentially life-threatening. Hives on the lips and throat can become severe enough to block air passage. Anaphylactic shock occurs when enough histamine is released to cause the blood vessels to dilate and release fluid into the tissues. This lowers blood volume and can result in heart failure.

A blood test can be performed to safely isolate over 400 different allergies, including dangerous food and environmental allergens. The Radio Allergo Sorbant Test (RAST) measures specific IgE antibodies using a blood sample. IgE is normally found in very small amounts in the blood; it is created as a defense mechanism when it senses an intruder. Separate tests are done for each potential allergen, and IgE results are graded from 0 to 6. For example, canine serum IgE will be high if a person has an allergy to dogs. The RAST is used if patients have pre-existing skin conditions or if patients cannot stop taking certain medications such as antidepressants or antihistamines for even a short period of time. (People must stop taking antihistamines several days prior to taking a skin allergy test because the medication can interfere with the results.) The RAST is a more expensive test that does not provide immediate results.

A number of other allergy tests are available, though many are considered unreliable according to The Academy of Allergy, Asthma, and Immunology. Applied kinesiology is a test that analyzes the loss of muscle strength in the presence of potential allergens. Provocation and neutralization testing involves injecting food allergens into the skin in different quantities, with the goal of determining the smallest dose needed to neutralize the symptoms. Sublingual provocation and neutralization is a similar test, except that the allergens are injected underneath the tongue. Cytotoxity testing involves watching for the reaction of blood cells after placing allergens on a slide next to a person’s blood samples.

After using a reliable testing method, the cause of an allergic reaction is often identified, and a physician is able to help a patient develop a treatment plan with the goal of controlling or eliminating the allergic symptoms. Those who are allergic to furry pets, pollen, and plants are prescribed mild medication or taught how to control their reactions with simple lifestyle changes, while those with food allergies learn to safely remove certain foods from their diets. Allergy sufferers who are prone to anaphylactic reactions are educated about life-saving techniques such as carrying the drug epinephrine and wearing medical alert bracelets. As soon as people understand their allergies, they can begin to experience an improved quality of life.

Questions 1-7
The passage describes three different types of allergy tests. Which of the characteristics below belongs to which type of test? In boxes 1-7 on your Answer Sheet, write

A if it is a characteristic of the skin-prick test.
B if it is a characteristic of the intradermal test.
C if it is a characteristic of the blood test.

1 A substance is inserted beneath the skin with a needle.
2 It is often done on a patient’s back.
3 It is advisable for patients who have skin problems.
4 It is not advisable for patients who have had serious allergic reactions in the past.
5 It shows results within half an hour.
6 It can cause red and white bumps on the patient’s skin.
7 It has a higher cost than other tests.

Questions 8-14
Complete the summary of the reading passage below. Choose your answers from the box below, and write them in boxes 8-14 on your Answer Sheet. There are more words than spaces so you will not use them all.

mold	smelling	identify	allegens
avoiding	medicines	eating	treat
antihistamine	anaphylaxis	causes	signs

Allergic reactions result from touching, breathing, or (8)……………………..certain substances called (9) ………………… Coughing or itching are two possible (10)………………….of an allergic reaction. More serious allergic reactions may result from certain insect bites, foods, or (11)………………………..A severe allergic reaction is known as (12)……………………….It can result in loss of blood volume and heart failure. Doctors can use a variety of tests to (13)……………………the source of an allergy. Treatment may include taking medication or (14)…………………………the substances that cause the allergic reaction.

the sacred pipe

The sacred pipe was one of the most important artifacts of the indigenous people of North America. In almost every culture, the sacred pipe was considered a gift from The Great Spirit. The Cree believed that the pipe, the tobacco, and the fire were given as parting gifts from the Creator, while the Iowa Black Bear clan believed that the pipe bowl and later the pipe stem emerged from the earth as gifts to the earth’s first bears. In most cases, the sacred pipe was considered a medium through which humans could pray to The Great Spirit, asking for guidance, health, and the necessities of life. In order for the prayers to reach the Great Spirit, they had to travel in the plumes of smoke from the sacred pipe. Because of its connection to the spiritual world, the pipe was treated with more respect than any human being, especially when the pipe bowl was joined to the stem.

Unlike the common pipe, which was used by average tribesmen for casual smoking purposes, the sacred pipe was built with precise craftsmanship. Before a pipe was carved, the catlinite (pipestone) was blessed and prayed over. The bowl of the traditional sacred pipe was made of red pipestone to represent the Earth. The wooden stem represented ail that grew upon the Earth. In the Lakota Society, as in many Native American tribes, the people believed that the pipe bowl also represented a woman while the pipe stem represented a man. Joined together, the pipe symbolized the circle of love between a man and woman. The sacred pipe was the only object that was built by both genders; men carved the bowl and stem while women decorated the pipe with porcupine quills. In many tribes the man and woman held onto the sacred pipe during the marriage ceremony.

Cultivating the tobacco was the responsibility of certain members of the tribe. Generally, tobacco was mixed with herbs, bark, and roots, such as bay- berry, mugwort, and wild cherry bark. These mixtures varied depending on the plants that were indigenous to the tribal area. Ceremonial tobacco was much stronger than the type that was used for everyday smoking. Rather than being inhaled, the smoke from the sacred pipe was puffed out the mouth in four directions.

In a typical pipe ceremony, the pipe holder stood up and held the pipe bowl in his left hand, with the stem held toward the East in his right hand. Before adding the first pinch of tobacco to the pipe bowl, he sprinkled some on the ground as an offering to both Mother Earth and the East. The East was acknowledged as the place where the morning star rose. Tribes believed that peace would evolve from wisdom if they prayed to the morning star.

Before offering a prayer to the South, the pipe holder again offered Mother Earth a sprinkling of tobacco and added another pinch into the bowl. The South was believed to bring strength, growth, and healing. While facing west the pipe holder acknowledged Mother Earth and prepared to thank the area where the sun sets. West was where the tribe believed the Spirit Helpers lived. At this time, they prayed for guidance from the spiritual world. The ceremony then proceeded to the North, which was thanked for blanketing Mother Earth with white snow, and for providing health and endurance.

After these four prayers, the pipe holder held the stem to the ground again and the tribe promised to respect and protect Mother Earth. Next, the stem was held up at an angle so that Father Sky could be thanked for the energy and heat he gave to the human body. Finally, the stem was held straight up and the tribe acknowledged The Great Spirit, thanking him for being the creator of Mother Earth, Father Sky, and the four directions.

After the pipe holder had worked his way around the four directions, he lit the pipe and passed it around the sacred circle in the same direction as the ceremonial prayers, starting from the East. Each member took a puff of smoke and offered another prayer. When the pipe had made a full circle, it was capped with bark, and the stem was removed. It was important for the stem and bowl to be stored in separate pockets in a pipe pouch. These pieces were not allowed to touch each other, except during a sacred pipe ceremony.

Pipestone, Minnesota, is considered hallowed ground for North American tribes. Regardless of their conflicts, tribes put their weapons down and gathered in peace in these quarries. According to the Dakota tribe, The Great Spirit once called all Indian nations to this location. Here the Spirit stood on the red pipestone and broke a piece away from the rock to make a giant pipe. He told his people that the red stone was their flesh and that it should be used to make a sacred pipe. He also said that the pipestone belonged to all native tribesmen and that the quarries must be considered a sacred place. Thus, people who had sacred pipes in their possession were considered caretakers, not owners.

Questions 15-19
Choose the correct letters, A-C, and write them in boxes 15-19 on your Answer Sheet

15 The sacred pipe was important in native American cultures because
A it was part of their spiritual practice
B it was used in gift exchanges between tribes
C it represented traditional handicrafts

16 The pipe was made of
A stone and wood
B bark and roots
C red clay from the Earth

17 The pipe was sometimes used at
A funerals
B births
C weddings

18 During the pipe ceremony, tribe members smoked
A plain tobacco
B a combination of plants
C only bark

19 Pipestone, Minnesota, is an important place because it is
A the site of a major battle
B the origin of the Dakota tribe
C source of stone for pipes

Questions 20-27
Complete the flowchart about the pipe ceremony. Write NO MORE THAN THREE WORDS for each answer.

The pipe holder takes the (20)………………..in his left hand and the (21)…………….in his other hand

The pipe holder offers tobacco to Mother Earth and (22)…………………the place where the morning star rises and then puts some in the pipe

The pipe holder prays to (23)………………..to bring strength, growth and healing and then prays to the remaining directions

The pipe holder points the pipe stem down and then up and prays to The Great Spirit, in appreciation for (24)……………., Father Sky and (25)……………..

The pipe holder passes the pipe around the sacred circle, and all members of the circle (26)………………..and pray

The bowl and stem are (27)………………..because they can only touch each other during the ceremony

bathymetry

The ocean floor is often considered the last frontier on earth, as it is a domain that remains greatly unexplored. Bathymetry, also known as sea-floor topography, involves measuring and mapping the depths of the underwater world. Today much of the ocean floor still remains unmapped because collecting bathymetry data in waters of great depth is a time consuming and complex endeavor.

Two hundred years ago most people assumed that the ocean floor was similar to the beaches and coastlines. During the nineteenth century, attempts to produce maps of the seafloor involved lowering weighted lines from a boat and waiting for the tension of the line to change. When the handline hit the ocean floor, the depth of the water was determined by measuring the amount of slack. Each of these measurements was called a sounding, and thousands of soundings had to be done just to get a rough measurement of a small portion of the ocean floor. Besides estimating the depth, these surveys helped in identifying large shipping hazards, especially near the shoreline. A naval officer published the first evidence of underwater mountains in a bathymetric chart in 1855.

During World War I, scientists developed the technology for measuring sound waves in the ocean. Anti-Submarine Detection Investigation Committee (ASDICs) was the original name for these underwater sound projectors, but by World War II the term sonar was adopted in the United States and many other nations. Sonar, which stands for Sound, Navigation, and Ranging, was first used to detect submarines and icebergs. By calculating the amount of time it took for a sound signal to reflect back to its original source, sonar could measure the depth of the ocean as well as the depth of any objects found within it. The first sonar devices were passive systems that could only receive sound waves. By the 1930s, single-beam sonar was being used to transmit sound waves in a vertical line from a ship to the seafloor. The sound waves were recorded as they returned from the surface to the ship. However, this type of sonar was more useful in detecting submerged objects than mapping the seafloor. Throughout World War II, technology improved, and active sonar systems that both received and produced sound waves were being used. It was the invention of the acoustic transducer and the acoustic projector that made way for this modem sonar. The newer systems made it possible to identify certain material, such as rock or mud. Since mud absorbed a good portion of a sound signal, it provided a much weaker echo than rocks, which reflected much of the sound wave.

The multi-beam sonar, which could be attached to a ship’s hull, was developed in the 1960s. With this type of sonar, multiple beams could be adjusted to a number of different positions, and a larger area of the ocean could be surveyed. Maps created with the aid of multi-beam sonar helped to explain the formation of ridges and trenches, including the Ring of Fire and the Mid-Ocean Ridge. The Ring of Fire is a zone that circles the Pacific Ocean and is famous for its seismic activity. This area, which extends from the coast of New Zealand to the coast of North and South America, also accounts for more than 75 percent of the world’s active and dormant volcanoes. The Mid-Ocean Ridge is a section of undersea mountains that extends over 12,000 feet high and 1,200 miles wide. These mountains, which zigzag around the continents, are generally considered the most outstanding topographical features on earth.

The invention of the side-scan sonar was another modem breakthrough for the field of bathymetry. This type of sonar is towed on cables, making it possible to send and receive sound waves over a broad section of the seafloor at much lower angles than the multi-beam sonar. The benefit of the side-scan sonar system is that it can detect very specific features over a large area. The most modem form of bathymetry, which is also the least accurate, is done with data collected by satellite altimetry. This method began to be used in the 1970s. This type of mapping relies on radar altimeters that receive echoes from the sea surface. These signals measure the distance between the satellite and the ocean floor. Unfortunately, due to water vapor1 and ionization, electromagnetic waves are often decelerated as they move through the atmosphere; therefore, the satellite receives inaccurate measurements. The benefit of using satellites to map the ocean is that it can take pictures of the entire globe, including areas that have not yet been measured by sonar. At this time, satellite altimetry is mainly used to locate areas where detailed sonar measurements need to be conducted.

Due to a constant flux of plate activity, the topography of the seafloor is ever-changing. Scientists expect bathymetry to become one of the most important sciences as humans search for new energy sources and seek alternate routes for telecommunication. Preserving the ocean’s biosphere for the future will also rely on an accurate mapping of the seafloor.

Questions 28-33
Complete the table below. Write NO MORE THAN THREE WORDS.

MAPPING THE OCEAN FLOOR

Method	First Used	Used For	How it Works
Weighted line	(28)………………..	determining (29)………………..	drop a line until it hits the bottom
(30)………………..	1930s	detecting objects underwater	send (31)………………to ocean floor
Multi-beam solar	(32)……………	mapping larger areas of the different directions	send multiple sound waves in
Satellite altimetry	1970s	taking pictures of (33)……………………	send signals from satellite

Questions 34-37
Match each description below with the ocean region that it describes. In boxes 34-37 on your Answer Sheet, write

A if it describes the Ring of Fire
B if it describes the Mid-Ocean Ridge

34 It is known for the earthquakes that occur there.
35 It is over one thousand miles wide.
36 It is a mountain range.
37 It contains the majority of the earth’s volcanoes.

Questions 38-40
The list below gives some possible reasons for mapping the ocean floor.

Which THREE of these reasons are mentioned in the reading passage?

Write the appropriate Roman numerals i-vi in boxes 38-40 on your Answer Sheet.

i Predicting earthquakes
ii Finding new fuel resources
iii Protecting ocean life
iv Understanding weather patterns
v Improving communications systems
vi Improving the fishing industry